1. Field of the Invention
The present invention relates generally to cups with lids for hot drinks, and more particularly to a cup lid having means for protecting the fingers of a person holding the cup from the heat of the cup contents.
2. Description of Related Art
Most beverage containers are made from paper materials that provide little resistance to thermal conductivity of the temperature of a hot or a cold beverage held in the container. These beverage containers provide an acceptable degree of thermal insulation when a beverage is warm, but when the beverage temperature is at or near the boiling point, such cups do not have sufficient insulation to protect a drink holder's hand or fingers. A large amount of heat is conducted from the beverage through the sidewall of the container making it impossible for the person to safely and comfortably hold the container. Often the person drinking from a hot cup puts the hot cup inside an empty cup to obtain sufficient insulation from the heat. However, the cup cost then doubles.
Another solution to the hot beverage container problem is described in U.S. Pat. No. 5,425,497 issued Jun. 20, 1995 to Jay Sorenson which discloses a cup holder in the form of a sheet with distal ends. A web is formed in one of the ends, and a corresponding slot is formed in the other end such that the ends interlock. Hence, the cup holder is assembled by rolling the sheet and interlocking the ends. The sheet can be an elongated band of pressed material, preferably pressed paper pulp and preferably formed with multiple nubbins and depressions. However, this is a separate piece in addition to the cup and lid requiring extra cost to purchase and time to assemble by interlocking the ends.
U.S. Pat. No. 4,190,173 issued Feb. 26, 1980 to Leroy W. Mason and Frederick J. Furner and assigned to Flambeau Products Corporation describes a beverage container having a doubled-walled construction. The double-walled construction may be made by mounting an inner container inside an overly large outer container with a seal between the inner and outer containers. However, this seal can release which partially destroys the thermal integrity of the container. If the liquid is extremely hot, such as at or near the boiling point, this type of cup will eventually conduct most of the heat to the outer wall.
U.S. Pat. No. 5,348,181, issued Feb. 26, 1980 to Bruce R. Smith and Reinhold Gerber and assigned to James River Corporation of Virginia, describes a drinking cup lid having tabs extending from opposite sides of the lid. The tabs are molded to have a slight curvature so that in the extended position, an outer surface is concave while an inner surface is convex. This concavo-convex design biases tabs in the extended position. As the tabs are pushed into the retaining position, the concavo-convex tab design combined with the curvature of the hinge forces the tabs to flex or buckle causing outer surface into a convex shape and inner surface into a concave shape whereby the gripping portion conforms generally to the curvature of sidewall. Simultaneously, the tabs are biased inwardly toward the cup sidewall. This biasing feature also forces a latching lip against the rim of the cup, thereby effectively securing the lid on the cup while maintaining an effective seal between a skirt of the lid receiving channel and the rim of the cup. However, the tabs structure and lid top structure are not conducive to low cost production. Such a locking lid is difficult to remove to add sugar or milk, and spillage can easily occur when trying to remove the locking lid. In addition, the tabs have minimal surface area for finger protection.